A free particle has kinetic energy equal to 35eV a)- What is the velocity of the particle? b)- If this velocity is known to within 0.2% accuracy, what is r of the position that particle? Assume that the mass of the particle is 2 x 10^-26 kg. Use h and give the answer in nm.

Respuesta :

Given:

kinetic energy of free particle, KE = 35ev

1eV = [tex]1.6\times 10^{-19}[/tex] J

mass of the particle, m = [tex]2\times 10^{-26}[/tex] Kg

accuracy in velocity= 0.2%= 0.002

Solution:

a) We know that

KE = [tex]\frac{1}{2}mv^{2}[/tex]

v = [tex]\sqrt{\frac{2KE}{m}}[/tex]

⇒ v = [tex]\sqrt{\frac{2\times 35\times1.6\times 10^{-19} }{2\times 10^{-26}}}[/tex]

v = [tex]2.36\times10^{4}[/tex] m/s

b) From Heisenberg's uncertainity principle:

[tex]\Delta x\Delta p = \frac{h}{4\pi}[/tex]

[tex]\Delta x.(mv) = \frac{h}{4\pi}[/tex]

[tex]\Delta x = \frac{h}{4\pi\times 2\times 10^{-26}\times2.36 \times 10^{4}\times 0.002}[/tex]

[tex]\Delta x = 0.56nm[/tex]